Previously, many types of holding and centering devices have been used to provide an effective means for holding a workpiece in a machine tool such as a milling or drilling machine.
The prior art listed below did not disclose patents that possess any of the novelty of the instant invention; however the following U.S. patents are considered related:
U.S. Pat. No.InventorIssue Date5,375,952LineDec. 27, 19946,679,659Lasch et al.Jan. 20, 20046,733,217 B2Schworer et al.May 11, 20046,745,455 B2Popp et al.Jun. 8, 20046,832,878 B2Elrod et al.Dec. 21, 2004
Line in U.S. Pat. No. 5,375,952 teaches a vertical milling and boring machine incorporating a gantry having two uprights on either side of a table. A tie joins the upper ends with a cross piece on the bottom of the table and a tool holder moves vertically on a carnage.
U.S. Pat. No. 6,679,659. issued to Lasch et al. is for a milling machine with a rotating spindle. The spindle is perpendicular to a workpiece stage that slants downward from a bed, and a chip collection chamber is positioned behind the work stage. Guides also are provided for a second carriage.
Schworer et al. in U.S. Pat. No. 6,733,217 B2 discloses a workpiece holding device for machine tools specifically a milling and/or drilling machine having a pivoting bridge supported between two walls. A drive motor pivots the bridge with a gear ring and a drive gear on the motor.
Popp et al. in U.S. Pat. No. 6,745,455 B2 teaches a machining apparatus having a lower and an upper housing. A tool holder is placed parallel to a tool axis on the lower side of the housing to hold a machining tool.
U.S. Pat. No. 6,832,878 B2 issued to Elrod et al. is for an automated quill drive assembly to retrofit a milling machine. A quill head includes a lower lug, a feed engagement control lever boss and a transmission cover. The assembly includes a housing for mounting to the lug. A sensor senses the position of the quill and provides output signals for both automatic and manual movement of the quill head.